Full text of "The Flow Of Gases In Furnaces"

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```INVERTED  WEIR

45

N Furnace. Fig. 27
Lyswa Furnace. Fig. 28

Dimensions of Hearth ............
16X2. 1 =33 m2 6
13X2 =26 rn2

Production per 24 hours . .       .....
f         3,800 pouds
2,900 pouds

Per sous/re meter
I       62,300 kg 1,860 kg
47,400 kg 1 850 kg

Coal consumed per 24 hours
f           800 pouds
409 pouds -J

Coal consumed per second .       ...
I       13,000 kg 0 kg 154
6,700 kg 0 kg 079

Ratio between weight of coal and weight of ingots  ..........
21.1 per cent
16 8 per cent

Gas volume per kilogram of coal burned with 50 per cent excess air supply                      ........
14 m3 04
9 m3 89

Gas,  volume burned per  second reduced to 0°
Qo = 2m3 16
Qo — 0 m3 78

Gas, volume burned per second at / = 1200°             .           .......

Q1200 = 4 m3 2

Height of roof above hearth at the right of the strangulation, computed by Yesmann's formula for a temperature of 1200° .........

hizooo ~ 0 m 530

Effective height ..... . ..........

0 m ffgff

Gas, volume per second at t = 700° . Height of roof at chimney or waste gas    opening    by    Yesmann's formula £ = 700°
Q7oo = 7m3697
/J,7QO   = ()    ft).    01
Q700 = 2m3780 &7oo — Om 479

Effective heieht .................
tnm-0 m,90
h™ — 0 m 850

" N " works. To what may this greater fuel consumption be
attributed. Evidently to the greater height between the roof
and the hearth of these furnaces.
Why was it found necessary at the " N " works to raise the
roof to a certain height above the hearth, while at the Lyswa works
it was found necessary to lower the roof to accomplish the same
result? An examination of the design of the " N" furnace
(Fig. 27) leads to a negative conclusion. Indeed, according to
Yesmann's formula a furnace will require less combustible wb^n
the roof is closest to the hearth. Accordingly the roof should be
brought down as low as possible.
The hot gases consist of a mixture of air, combustible gases and
the products of their reaction upon each other. The combustion
takes place while the hot gafces are passing through the furnace;
C1) The quality of the coal is not considered in this computation.```